Make up your mind to do the puzzle again (7)
I believe the answer is:
resolve
'make up' is the definition.
The answer and definition can be both related to thinking as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'your mind to do the puzzle again' is the wordplay.
I cannot quite see how this works, but
'again' could be 're' (prefix meaning 'again') and 're' is found within the answer.
The remaining letters 'solve' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for resolve that I've seen before include "12 [STIFF UPPER LIP]" , "Settle (a matter)" , "Settle, conclude" , "Settle, decide" , "Settle (a dispute)" .)